Process for treating non-kerations material with a polythiol resin and an aminoplast and the product obtained

ABSTRACT

The present invention relates to a process for improving the mechanical properties of cellulosic fibres. The effects are achieved by impregnating the fibres, especially those treated with an aminoplast, with a resin containing at least two mercaptan groups linked through poly(oxyalkylene) chains to a radical of a polyhydric alcohol.

United States Patent [191 Massy et al.

[451 Apr. 1, 1975 PROCESS FOR TREATING NON-KERATIONS MATERIAL WITH APOLYTHIOL RESIN AND AN AMINOPLAST AND THE PRODUCT OBTAINED [75]Inventors: Derek James Rowland Massy,

Linton; Kenneth Winterbottom, Whittlesford, both of England [73]Assignee: Ciba-Geigy AG, Basle, Switzerland 22 Filed: May 16,1973

21 Appl. N0; 360,874

Related US. Application Data [63] Continuation of Ser. No. 156.052, June23, 1971,

abandoned.

[30] Foreign Application Priority Data July 2, 1970 United Kingdom3240/70 [52] US. Cl 8/ll5.6, 8/116 R, 8/182, 8/184, 117/1394, 117/1395 A[51] Int. Cl. D06c 29/00 [58] Field of Search 8/115.6, 116 R, 128,127.6, 8/182,l84;117/141,139.4,139.5 A

[56] References Cited UNITED STATES PATENTS 3,706,527 l2/l972 Dobinsonet a1 8/l 15.6 X 3,753,649 8/1973 Dobinson et a1 8/115.6 X

Primary Examiner Stephen J. Lechert, Jr. Attorney, Agent, orFi'rm.loseph G. Kolodny; Edward McC. Roberts; Prabodh l. Almaula [57ABSTRACT 19 Claims, No Drawings PROCESS FOR TREATING NON-KERATIONSMATERIAL WITH A POLYTHIOL RESIN AND AN AMINOPLAST AND THE PRODUCTOBTAINED This is a continuation of application Ser. No. 156,052, filedon June 23, 1971 now abandoned.

This invention relates to a process for modifying cellulosic materialsin fibrous form, and to materials so treated.

It is well known to treat cellulosic materials with aminoplasts.Cellulosic textiles are often treated with these substances to impartdimensional stability, resistance to creasing. or permanent mechanicaleffects such as pleats and seersucker effects. One drawback is that thetear-strength of the treated textile is often lowered, another is thatthe treated textile is often harsher. These drawbacks have, to a certainextent, been overcome by incorporating softening agents such aspolyethylene emulsions or adducts of ethylene oxide with phenols oramines, but for many purposes these agents are insufficiently effective.

It has now been found that, by the use of certain thiolterminatedpoly(oxyalkylene) substances, preferably in conjunction with particularaminoplasts, cellulosic materials having improved properties, inparticular textiles having a fuller, softer handle, can be obtained.

Accordingly, the present invention provides a process for modifyingcellulosic fibres which comprises 1. treating the fibres, in the absenceof keratinous material, with,

A. a polythiol having at least two thiol groups per molecule andcontaining a. radical of a polyhydric alcohol,

b. bound to this radical, at least two poly(oxyalkylene) chains,

c. bound through oxygen atoms to carbon atoms in the saidpoly(oxyalkylene) chains, at least two residues selected from the groupcomprising an acyl residue of a thiol-containing aliphatic carboxylicacid and the residue, after removal of a hydroxyl group, of athiol-containing aliphatic alcohol,

and, optionally,

B. an aminoplast which is free from ethylenic unsaturation, and

2. curing the polythiol and/or the aminoplast on the fibres.

The present invention further provides cellulosic fibrous materials, inthe absence of keratinous material, bearing thereon a polythiol asaforesaid in the cured or still curable state.

If an aminoplast is used, treatment of the fibres with the aminoplastand the polythiol, and curing the polythiol and aminoplast, can takeplace in any desired sequence. For example, the fibres may beimpregnated with a mixture of the aminoplast and the polythiol, and thenthe aminoplast and/or the polythiol are cured. Or the fibres may beimpregnated first with the polythiol and then with the aminoplast, orvice versa, and then the aminoplast and/or polythiol are cured.- Or theaminoplast can be cured on the fibres, which are then treated with thepolythiol and the polythiol is cured.

Cellulosic fibres which may be subjected to the process of thisinvention include cotton, regenerated cellulose, including viscose andcuprammonium rayons, jute, linen, hemp, ramie, sisal, paper, and blendsof these cellulosic materials with synthetic fibres. The

term cellulosic fibres includes fibres comprised of a substance derivedfrom a cellulose in which some, but not all, of the three availablehydroxyl groups per anhydrogluco unit have been chemically modified, egby 5 acylation, etherification, or cyanoethylation. Thus,

methyl cellulose and cellulose monoacetate are included but not, forexample, cellulose triacetate. The cellulosic materials are preferablytextiles, including yarns, threads, woven, non-woven and knittedfabrics, and garments.

Mixtures of two or more cellulosic fibrous materials, and blends withsynthetic fibres, may also be treated, but it should be clearlyunderstood that blends of cellulosic fibrous materials with keratinousmaterial are not included within the scope of the present invention.

Polythiols used in the process of this invention preferably contain two,three, or up to six thiol groups per molecule. Especially good resultshave been obtained with those containing two or three thiol groups permolecule.

Preferred polythiols are those having a molecular weight between 400 and10,000 particularly those of formula in which m is an integer of atleast 1 and may have different values in each of the p and (q-l) chains,

n is a positive integer of at most 2,

p is a positive integer of at least 2,

q is a positive integer such that (p q) equals at least 3 and at most 7,

each alkylene group contains a chain of at least 2 and at most 6 carbonatoms between consecutive oxygen atoms,

R represents an aliphatic radical containing at least 2 carbon atoms,

and X represents an aliphatic radical containing at least one thiolgroup.

The oxyalkylene units in individual poly(oxyalkylene)chains may bedifferent. They may be substituted, if desired, by e.g., phenyl orchloromethyl groups, 55 There may thus be used the partially or fullyesterified compounds of the formula in which R, alkylene, m, p, and qhave the meanings previously assigned, and r is a positive integer whichmay be as high as 18 or even 24.

Further preferred are esters of the formula in which alkylene, m, p, andq have the meanings previously assigned,

14 is a positive integer of at most 2,

and R represents an aliphatic radical having at least 2 and at most 6carbonatoms.

Yet further preferred are esters of formula (-O-olkylen e9 co. C H SH 2]1 -alkylene')-0.CO.C 11 SH] and 2 l R o alkylenel; 0.CO. C H SH:l i 3 inwhich alkylene. m, and u have the meanings previously assigned,

p represents2 or 3,

p is zero or 1, such that (p, p is 2 or 3,

P denotes an integer of at least 3 and at most 6,

and R represents an aliphatic hydrocarbon radical having at least 3 andat most 6 carbon atoms.

Still further preferred are esters bases on based hexanel ,2,5-tri ol,hexane-1,2,6-triol, ethylene glycol, or propylene glycol, and ethyleneoxide and/or propylene oxide, i.e. those of the formulae in (oc n l CH2(00 H 0.00.0 ll SH,

t 21; m u

0H (0G H o.co.c rr sn CH (oc a o.co.c i sii (cn cu 3- H (0091 9; 0 co. cn su I 4 CH2 (OC H O.CO.C H SH on (oc t-t on CH2 (OC H O.CO.C H SH 1. 2tm CO u Zu t QQm in which m and u have the meanings previously assigned,and t is an integer of at least 2 and at most 3; and

(cu l 2 CH r- (o (CH )mococH su the polythiol having an averagemolecular weight between 1000 and 7500, where m has the meaningpreviously assigned. Polythiol esters most preferred for the purposes ofthe present invention are those obtained from glycerol or propyleneglycol, propylene oxide, and thioglycollic.

acid, i.e. of formula 0H (oc n 000011 5)! cH (00 11 ococn sa m2 (oc nococn srr having a molecular weight within the range 1,000 to 5,000, oreven 7,500,

, CH2 (OC ll l ocociu sn on (00 O Cl-l (OC H OCOCH SH CH CH' 3 CH (oc nOCOCHQSH having a molecular weight within the range 1000 to 7500, wherem has the meaning previously assigned. Such esters are commerciallyavailable.

These thiol-terminated poly(alkylene oxide) esters are readily preparedby the reaction ofa polyhydric alcohol with an alkylene oxide followedby partial or complete esterification of the terminal hydroxylgroupswith a mercaptocarboxylic acid.

Suitable polyhydric alcohols include ethylene glycol, poly(oxyethylene)glycols, propylene glycol, (poly(oxypropylene) glycols,propane-1,3-diol, poly(epichlorohydrin)s, butane-1,2-diol, butane-1,3-diol, butane-l ,4-diol, butane-2,3-diol, poly(oxy-1,1-dimethylethylene) glycols, poly(tetrahydrofuran)s, glycerol, 1, l,l-trimethylolethane, 1,1 ,1- trimethylolpropane, hexane-l,2,5-triol,hexane-1,2,6- triol, pentaerythritol, dipentae'rythritol, mannitol,sorbitol, and adducts of allylene oxides with ammonia or amines, suchasdiethanolamine and tetrakis (N-(2- hydroxyethyl) ethylenediamine.Suitable alkylene oxides include ethylene oxide, propylene oxide,tetrahydrofuran and, less preferably, epichlorohydrin. If desired, thepolyhydric alcohol may be treated with one alkylene oxide, say propyleneoxide, and then tipped with a different alkylene oxide, such as ethyleneoxide.

The preferred mercaptocarboxylic acids for the esterification are, asalready indicated, thioglycollic acid (2-mercaptoacetic acid) and2-mercaptopropionic acid, but other mercaptomonocarboxylic acids whichmay be used include mercaptoundecyclic acid and mercaptostearic acid.

Preferred thiol-terminated poly(alkylene oxides) for use in theinvention include those of formula in which R denotes OH,(Oalkylene),.Ol-I,O.CO.- C H SH, or (O-alkylene),.O.CO.C,,H ,,SH,

R, alkylene, m, p, q, and u have the meanings previously assigned,

and v is an integer of at least 1 and may have different values in eachof the p chains.

The oxyalkylene units in the individual poly(oxyalkylene) chains maylikewise be different, but are preferably the same, and may besubstituted if desired by e.g. phenyl or chloromethyl groups.

Preferred among such ethers are those whichare also of formula (-O-alkylene-) OCH CHCH SH in which alkylene, R,m,R p, and q have the meaningspreviously assigned, and further preferred are those of the formulaO-alkylene) PCH CHCH SH OCH CHCH in which R t,'m, and 12 have themeanings previously assigned. The ethers in which R denotes Ol-l may beprepared in a known manner by reaction of an alkylene oxide with apolyhydric alcohol, etherification of the hydroxyl groups of the productwith epichlorohydrin, and treatment with sodium hydrosulphide to replacethe chlorine by a sulphhydryl group( see U.S. Pat. No. 3,258,495, andUnited Kingdom Specifications 1,076,725 and 1,144,761 In many cases theaverage 'number of thiol groups per molecule is not an integer but, forexample, may be 2.6. This is attributable partly to the'replacement ofthe chlorine atoms by the SH group not going to completion, and partlyto sidereactions: for example, the chlorohydrin ether obtained byreaction with epichlorohydrin may also react with epichlorohydrin, soforming an ether which contains two replaceable chlorine atoms perhydroxyl group originally present in the polyhydric alcohol.

Ethers of formula in which R t, m, v, and 12 have the meaningspreviously assigned, are likewise particularly preferred. Ethers inwhich R denotes -(O-alkylene),-OH may be prepared by treating theproduct which is obtained from epichlorohydrimthe alkylene oxide and thepolyhydric alcohol, first with an alkylene oxide, and then with sodiumhydrosulphide see United Kingdom Specification 1,144,761).

The most preferred ethers are those of formula where m has the meaningpreviously assigned, especially such ethers having a molecular weightwithin the range 700 to 3,500 or up to 7500.

drocarbons containing not more than three carbon atoms, such as thedry-cleaning solvents, carbon tetrachloride, trichloroethylene, andperchloroethylene.

The amount of the polythiol to be used depends on the effect desired.When the polythiol is used without an aminoplast, then,-for mostpurposes, from 0.5 to percent by weight calculated on the weight of thematerial to be treated is preferred. Woven fabrics usually re-' quirefrom 1 to 10 percent by weight of the polythiol, but rather smallerquantities are usually needed on knitted fabrics, say from 1 to 5percent by weight. The hand, or handle, of the treated material will, ofcourse, depend on the amount of polythiol employed, and by simpleexperiment the least amount required to give the desired effect mayreadily be determined. Further, the composition of, and the constructionof, fabrics composed of the fibres also influence the amount ofpolythiol required. When the polythiol is used in conjunction with anaminoplast, the amount of polythiol will be smaller, say from 0.1 to 3percent by weight calculated on the weight of material to be treated.

The aminoplasts employed contain, per molecule, at least two groups offormula CH OR directly attached to an amidic nitrogen atom or atoms,where R denotes a hydrogen atom, an alkyl group of from one to fourcarbon atoms, or an acetyl group. Examples of such aminoplasts are thelV-hydroxymethyl,N- alkoxymethyl, and N-acetoxymethyl derivatives offollowing amides and amide-like substances.

1. Urea, thiourea, and the cyclic ureas having the formula in which Ydenotes either a group of formula.

I Hc cit,

HN NH methyl, methoxy, and hydroxy groups, and which may be interruptedby -CO-,-O-, or

COH-

2-one), dimethylpropyleneurea (5 ,5- dimethylhexahydro-ZH-pyrimid-2-onedimethylhydroxypropyleneurea and dimethylmethoxypropyleneurea (i.e.4-hydroxyand 4-methoxy-5,5- dimethylhexahydro-2H-pyrimid-2-one), andS-ethyland 5-(2-hydroxyethyl)-triazin-2-one.

ll. Carbamates and dicarbamates of aliphatic monohydric and dihydricalcohols containing up to four carbon atoms, e.g. methyl, ethyl,isopropyl, 2- hydroxyethyl, Z-methoxyethyl,Z-hydroxy-n-propyl, and3-hydroxy-n-propyl carbamates, and ethylene and 1,4- butylenedicarbamates.

lll. Melamine and other polyamino-l,3,5-triazines.

'If desired, aminoplasts containing both. N- hydroxymethyl andN-alkoxymethyl, or N- hydroxymethyl and N-acetoxymethyl groups, may beused, for example, a hexamethylol melamine in which from 1 to 5 of themethylol groups have been so etherified or esterified.

The aminoplast is usually applied as such but, if desired, when aurea-formaldehyde: or melamineformaldehyde product is to be used, it maybe formed in situ in a conventional manner from a ureaformaldehydeconcentrate or melamine-formaldehyde concentrate and the requisiteadditional urea or melamine.

The aminoplasts employed are, in general, soluble in water and may beapplied from aqueous solution; or they may be applied fromaqueousemulsions, fromsolutions in the dry-cleaning solvents alreadymentioned,

or from solutions in mixtures of water and a suitable cosolvent, such asmethanol.

The proportions of the polythiol and the aminoplast can vary widely;usually there will be employed, per

thiol group equivalent of the polythiol, from 2 to 50 or even 75, butusually from 5 to 40, N-methylol, N-'

alkoxymethyl or N-acetoxymethyl group equivalents of the aminoplast.

The desired effects may not be fully obtainable until substantially allthe polythiol on the material has cured. At ordinary temperatures thismay take from 5 to 10 days or even longer. The curing reaction can,however, be accelerated greatly by the use of a catalyst and generallyitis preferred to add the catalyst to the material to be treated'at thesame time as the polythiol is applied, although it maybe added before orafterwards if desired. The'curing time can be controlled by selecting anappropriate catalyst and the choice of curing time will depend on theparticular application of the process according to the invention.

The catalysts may be bases, siccatives, sulphur, sulphur-containingorganic compounds, and free-radical catalysts such asazodi-isobutyronitrile peroxides and hydroperoxides, or combinations ofthese.

As organic bases there may be used primary or secondary amines such asthe lower alkanolamines, e.g. monoand di-ethanolamine, and loweralkylene polyamines, e.g. ethylenediamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine, propanel,2- and-l.3-diamine, and hexamethylenediamine. As inorganic bases there may beused the water-soluble oxides and hydroxides, e.g. sodium hydroxide,watersoluble, strongly basic salts such as trisodium phosphate, disodiumtetraborate, and sodium carbonate, and also ammonia.

Sulphur-containing organic compounds which may be used as catalystsinclude those in which the sulphur atoms are not exclusively present asmercaptan groups, especially mercaptobenzothiazoles and theirderivatives, dithiocarbamates, thiuram sulphides, thioureas,disulphides, alkyl xanthogen sulphides and alkyl xan thates.

Examples of siccatives are calcium, copper, iron, lead, cerium, andcobalt naphthenates.

Examples of suitable peroxides and hydroperoxides are cumenehydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, dilaurylperoxide, methyl ethyl ketone peroxide, di-isopropyl peroxydicarbonate,and chlorobenzoyl peroxide.

Yet other catalysts are salts of a heavy metal with an acid having anacid strength log pK) below 5, or chelates of a heavy metal, includingchelates which are also salts. By heavy metal" is meant one classifiedas heavy in Langes Handbook of Chemistry, revised 10th Edition,McGraw-Hill Book Co., at pp. 60-61, that is, a metal of group 1B, [1B,lllB, IVB, VB, VIB, VllB, or VlIl, a metal of group IIlA having anatomic number of at least 13, a metal of group IVA having an atomicnumber of at least 32, or a metal of group VA having an atomic number ofat least 51. Preferably the metal is a member of group IB, llB, IVB, VB,VlB, VIlB, or Vlll, particularly the first series of such metals, i.e.titanium, vanadium, chromium, manganese, nickel, and especially iron,cobalt, and copper. Suitable saltforming acids are mineral acids,especially hydrochloric, hydrobromic, nitric, sulphuric, phosphorous,and phosphoric acids, and organic acids such as chloroacetic, fumaric,maleic, oxalic, salicylic, and, more especially citric acid. Suitablechelating agents include those in which the chelating atoms are oxygenand/or nitrogen, for example, 1,2- and l,3-diketones such asacetylacetone, 'alkylenediamines such as ethylenediamine, and moreparticularly, ethylenediaminetetraacetic acid.

The amount of catalyst used can vary widely. Ingen- I eral from 0.1 topercent, and usually 1 to 10 percent by weight based on the weight ofthe polythiol used is required, although much larger quantities can beused.

Curing of the polythiol is also assisted by using elevated temperaturesand if especially rapid results are required then temperatures in therange to 180C may be used. High humidities also tend to acceleratecuring in the presence of catalysts. Curing is also promoted by workingat a pH in the range 7.5 to 12.

The aminoplast, where one is added, may be cured under the usualconditions, i.e. at room temperature or at elevated temperatures. Themechanism by which the polythiol exerts its effect in conjunction withthe aminoplast is not known. It is believed that either the SH group ofthe mercaptan reacts with the N-methylol groups (present as such orformed in situ from esterified or etherified N-methylol groups), oroxidation of the SH groups occurs, molecules of the polythiol beingcoupled by means of disulphide bridges. The utility of this invention,however, does not depend on the truth of this belief.

In many cases it is desirable to use a catalyst for curing theaminoplast. Catalysts which may be used include conventional materialssuch as latent acid compounds (which may be metal salts), or mixturesthereof, or certain basic substances. Ammonium salts which are latentacids, developing acidity in the mixture on heating, include ammoniumchloride, ammonium dihydrogen phosphate, ammonium sulphate and ammoniumthiocyanate. These ammonium salts may be used admixed with metal saltswhich also have a similar catalytic effect. Amine salts may also beused, eg 2- amino-2-methylpropanol hydrochloride. Among the suitablelatent acid metal salts are zinc nitrate, zinc fluoroborate, zincchloride, zirconium oxychloride, magnesium chloride, magnesiumfluoroborate, and magnesium dihydrogen orthophosphate. These catalystsare generally used at concentrations of 0.3 to 5 percent by weight,calculated on the weight of the fibres.

There may also be used stronger acids such as hydrochloric or sulphuricacids which may be used as an aqueous solution (say, as 4- to 8- normalsolutions) or which may be dissolved in a mixture of water and a solventwhich is immiscible or partly miscible with water, andalso acidic gases.Basic substances which may be used include sodium bicarbonate and sodiumcarbonate. When strong acid catalysts are used, in liquid or gaseousform, heating may not be necessary. In other cases, it may be necessaryto heat the treated material, e.g. at a temperature of from 80 to 200Cfor from 30 seconds to 10 minutes, and preferably at from 120 to 180Cfor from 2 to 7 minutes.

The polythiol, and the aminoplast and catalyst if used, can be appliedto the material in conventional ways. For example, where fabric is tobe'treated, they may be padded on, or the material may be immersed in abath. If garments or garment pieces are to be treated then it isconvenient to spray them with the agents, and more convenient still totumble the garments with the agents dissolved in an organic solvent. Forthe latter method a dry-cleaning machine using a dry-cleaning solvent isparticularly useful.

A crease-resistant finish may be applied to a cellulosic textile fabricby impregnating with the polythiol,

. an aminoplast and a catalyst for curing the aminoplast,

drying the textile, usually in a flat configuration, and then curing atleast the aminoplast, normally at a high temperature. Compared to fabrictreated with aminoplast only, fabric treated in the above manner isconsiderably softer and has either substantially improved drycrease-resistance with no further loss in tear strength or substantiallyimproved tear strength with no loss in dry crease-recovery.

A cellulosic textile fabric having good wet creaserecovery propertiesmay be obtained by impregnating the fabric in an aqueous medium with anaminoplast (such as methylolated dihydroxyethylene urea) and a strongacid catalyst (e.g. hydrochloric acid) for curing the aminoplast,keeping the fabric wet and in an uncreased state (e.g. for 16-24 hours),rinsing the fabric if desired, neutralising the catalyst, drying thefabric if necessary, and treating with the polythiol (with an amine orother catalyst if necessary). Material aftertreated with the polythiolhas much better 'wet creaserecovery than, and equal tear strength to,fabric treated with aminoplast alone. Cellulosic textile fabrics havingboth wet and dry crease-recovery may be obtained by similar treatment,and curing the aminoplast while the fabric is moist. By wet we meanhaving a water content of more than 20 percent by weight, and by moistwe mean having a water content of from to percent by weight, bothcalculatedon the weight of the bonedry fabric.

A durablypressed cellulosic garment may be made by treating a cellulosicfabric in piece form with the polythiol (say, as an aqueous emulsion ora solution in an organic solvent), an aminoplast, and a catalyst for theaminoplast, and drying the impregnated fabric, fashioning the sensitisedfabric into a garment, inserting any requisite creases or pleats andcuring the aminoplast at elevated temperature, e.g. in an oven. Comparedwith garments treated with aminoplast only, the garment is much softert0 the touch and has a much better balance of crease-recovery andstrength.

Thiol C Thiol C denotes a poly (2-hydroxy-3-mercaptopropyl) etherprepared from a glycerol-propylene oxide adduct having an averagemolecular weight of 4,800, epichlorohydrin, and sodium hydrosulphide. Ithad a mercaptan content of 0.32 equiv./kg, corresponding to 2.6 SHgroups per average molecule.

Thiols D-L These Thiols were made in a similar manner to Thiol A. Theircompositions are given in the following Table.

Polyol Esterifying Mercaptan Mercaptan Thiol Alcohol Alkylene oxide M.W.acid Functionality content (Theoretical) eqjkg D Glycerol Propyleneoxide 3000 Thioglycollic 3 0.72 E Glycerol Propylene oxide 6200Thioglycollic 3 0.30 F Glycerol Propylene oxide 700 Thioglycollic 3 2.9G Glycerol Propylene oxide 4000 Thioglycollic 2 0.41 H PentaerythritolPropylene oxide 2000 Thioglycollic 4 1.22 l 1,2,6-Hexane-triol Propyleneoxide 1500 Thioglycollic 3 1.63 J Glycerol Propylene oxide 40002-Mercapto- 3 0.6

propionic K Butane-1.4-diol Tetrahydrofuran 1000 Thioglycollic 2 1.66 LGlycerol Propylene oxide 1000 3-Mercapto- 3 2.3

propionic Thiol G is a partial cster.

The compositions used in the processof this mven- Thiol M tion, viz.those containing a polythiol as aforesaid, as an aqueous dispersion oremulsion, or as a solution in an organic solvent, and optionally acatalyst and an amino plast, may also contain antisoiling, antistatic,bacteriostatic, rotproofing, flameproofing, and wetting agents. They mayalso contain water-repellents such as paraffin wax, and fluorescentwhitening agents.

The following Examples illustrate the invention. Unless otherwisespecified, partsand percentages are by weight. The thiols used wereprepared as follows:

Thiol A A mixture of 800 g (0.2 g-mol.) of a polyoxypropylene triolhaving an average molecular weight of 4,000 and made from glycerol andpropylene oxide, (Polyol A), 55.2 g (0.6g-mol.) of thioglycollic acid, 5g of toluene-p-sulphonic. acid, and 350 ml of toluene, was heated toreflux with stirring for 4 hours in an atmosphere of nitrogen. Water10.8 ml, 0.6 g-mol.) formed during the reaction was removed as itsazeotrope with toluene. The mixture was cooled and washed with water,and the organic layer was separated. On removing under vacuum thesolvent from the organic layer there remained 793 g (94 percent of thetheoretical yield) of the desired tris(thioglycollate), (Thiol A),having a mercaptan content of 0.59 equiv./kg.

Thiol B A mixture of polyoxypropylene glycol (1000 g) having an averagemolecular weight of 2000 (0.5 g-mol.) thioglycollic acid (92 g, 1g-mol.), toluene-p-sulphonic acid (5 g), and perchloroethylene (750 ml),was heated Thiol M was prepared in a similar manner to Thiol C.

Emulsion A Thiol A 500 g Emulsifying agent I 50 g water 450 g Thecomponents were mixed at room temperature with a Silverson mixer until auniform emulsion resulted. Emulsifying agent 1 denotes an adduct of amixture of C and C aliphatic primary amines (1 mol.) and ethylene oxidemols).

Emulsions B & C

These were prepared in the same manner as Emulsion A, but substitutingThiols B & C for Thiol A.

Emulsion D Thiol D 500 g Emulsifying agent 1 50 g sodiumcarhoxymethylcellulose 5 g water 445 g The components were emulsified asbefore.

Emulsions E-L EXAMPLE 1 Samples of a bleached cotton poplin (108 g persquare metre) were padded with Liquors l-4 so that the take-up was 70percent. The samples were dried for minutes at 70C on tenter frames totheir original dimensions and then the compositions were cured. Thecuring conditions, and measurements of certain properties of the treatedsamples, are given in Table l.

Liquors 14 had the following compositions:

Liquor l Aminoplast A 60 g/litre MgCl .6H ,O 2O g/litre in waterAminoplast A is a co-condensate of a methylated hexamethylol melaminecontaining 4.5 methoxymethyl groups per molecule and dimethylolethyleneurea.

Liquors 2-4 Liquors 2-4 were the same as Liquor l, but contained inaddition 30 g per litre of Emulsions A-C respectively.

In this, and the following Examples, the dry crease angles of thetreated samples were measured by the Monsanto method, twelve specimens(six folded warpwise, six folded weftwise) being used in each test, thespecimens were creased under a 2 kg load for 3 minutes and allowed torecover, suspended over a wire, for 3 minutes before the crease angleswere measured. The yalues given in the Tables are the average of the sixobtained by adding the warpwise value to the corresponding weftwisevalue and dividing by two. Tear strengths Liquor 1 Thiol C EXAMPLE 2Samples of the bleached cotton poplin used in Example 1 were padded withLiquor 1 so that the take-up was percent, and dried for 10 minutes at70C on tenter frames to their original dimensions. The samples wereheated for 5 minutes at C to cure the aminoplast. Next, some of thesesamples were padded with a 0.7 percent solution of a thiol inperchloroethylene, the pick-up of the thiol being 1 percent, and thenthey were dried as before and heated for 3 /2 minutes at C. The creaseangle and tear strengths were measured and they are shown in Table 11.

Table I1 Treated with Crease angle Tear strength '(g) Untreated Liquor 1only Liquor l Thiol A Liquor 1 Thiol B Liquor l Thiol C EXAMPLE 3 Poplinsamples were padded with a 0.7 percent solution of the thiol inperchloroethylene to 1 percent pickup of the thiol. The samples weredried for 10 minutes at 70C on tenter frames, heated for 3 /2 minutes at160C, then treated with Liquor l to 70 percent pickup. The samples weredried in the same manner as before, and cured for 5 minutes at 145C.Measurements of the tear strength and crease angle are given in Table111.

Table III Treated with Crease angle Tear strength (g) Untreated 49 528Liquor 1 only 99 208 Liquor 1 Thiol A 1 19 228 Liquor 1 Thiol B 116 320131 352 EXAMPLE 4 In order to ascertain the machine-washability .ofcotton poplin treated in accordance with the present invention, sampleswere padded to 70 percent pick-up with Liquors 1 and 2. After curing,the handle of the material was noted, and the crease angle and tearstrength were measured. The samples were then washed three times, withintermediate tumble drying, in an English Electric Reversomatic washingmachine set on programme 1 (90C wash) using an aqueous solutioncontaining 2 g/litre soap and 0.8 g/litre soda ash. The crease angle andtear strength were again measured: the results are given in Table IV.

Table IV Cure Handle Crease angle Tear strength (g) Liquor Time Temp.Original Washed Original Washed Original Washed (mins) ("C) l 5 14(1harsh soft 92 73 240 256 2 5 140 soft. soft, 1 16 82 320 256 silky silkyZ 3 A 160 soft, soft, 1 24 97 256 272 silky silky EXA E 5 SofteningAgent A is a commercially-available prod- Aqueous liquors 5 and 6 wereprepared containing 1 the following ingredients, expressed in grams perlitre of water:

Liquor 5 Liquor 6 Aminoplast A 60 60 Mgcl bH o 20 20 Emulsion A 30 60Samples of bleached cotton poplin were padded with the above liquors,and also, for comparative purposes, with Liquor 1, so that the uptakewas 70 percent. The samples were dried for minutes at 60C on tenterframes, then cured for 3 /2 minutes at 160C. The crease angles and tearstrengths were measured, the samples were then washed three times asdescribed in Example 4, and the tear strengths and crease angles weremeasured again. Table V shows the results obtained.

Table V Original Washed Liquor Crease Tear Crease Tear angle strengthangle strength lg) (g) EXAMPLE 6 In order to compare the effects of thecompositions containing an aminoplast and a polythiol with compositionscontaining an aminoplast and a conventional softening agent (SofteningAgent A) samples of a cotton poplin were treated to 64 percent uptakewith the following aqueous liquors:

Liquor 7 s 9 10 11 Emulsion A 1O 30 Softening Agent A 10 30 MgCl .6H O15 15 15 15 15 Aminoplast B 150 150 150 150 150 These figures refer tograms per litre.

Aminoplast B is a 50 percent aqueous solution containing equimolaramounts of the pentamethyl ether of hexamethylol melamine andbis(N-hydroxymethyl) ethyleneurea.

not sold for use with aminoplasts. V

The samples were dried at 110C for 1 minute and cured at 150C for 5minutes. They were then stored at room temperature. After 1 day, some ofthe samples were washed in a Hoovermatic washing machine for minutes at95C with a solution containing soap flakes (5 g per litre) and sodiumcarbonate (2 g per litre), and then tested. The remaining samples weretested after 5 days storage at room temperature.

The results are given in Table VI.

Table VI Original Washed Liquor Crease Tear Crease Tear angle strengthangle strength From this Table it may be seen that, by using the thiol,a greatly improved crease angle is obtained for a given tear strength,compared to that obtained using the conventional softening agent.

EXAMPLE 7 Bleached cotton poplin was padded with a solution of Thiol Ain perchloroethylene to 1 percent pick-up of the thiol. The samples weredried for 10 minutes at 60C and kept at room temperature for 24 hours.They were then treated with an aqueous solution containing an aminoplastand 4 g per litre of ammonium sulphate to percent uptake of solution,dried for 10 minutes at 60C, and cured for 3% minutes at C. The

crease angles and tear strengths were measured, and are reported inTable V11. Comparative figures for poplin which had not been treatedwith Thiol A are also Aminoplast C is a 50 percent aqueous solution ofbis(N-hydroxymethyl) dihydroxyethyleneurea.

Aminoplast D is a 75 percent aqueous solution of a methylatedmethylolmelamine. containing on average three N-methoxymethyl and twoN-hydroxymethyl groups per molecule.

Aminoplast E is the pentamethyl ether of hexamethylolmelamine.

EXAMPLE 8 Bleached cotton poplin was padded to 70 percent uptake withthe following aqueous liquors: (concentration in g per litre) Liquor 1213 l4 l Emulsion A 30 3O Aminoplast C 120 120 Aminoplast D 100 100 (NH.SO 4 4 4 4 The samples were dried for minutes at 60C, then cured for 3/2 minutes at 160C. The crease angles and tear strengths were measured,and the results are given a Bleached cotton poplin was padded to 70percent uptake with Liquors l4 and 15 as described in Example 8, or withan aqueous liquor (Liquor 16) containing 90 g per litre of Aminoplast Eand 4 g per litre of ammonium sulphate, dried for 10 minutes at 60C, andcured for 3 /2 minutes at 160C. Some samples were then treated with asolution of Thiol A in perchloroethylene to give 1 percent pick-up ofthe thiol. After being dried for 10 minutes at 60C, the samples werecured for 24 hours at room temperature, and the crease angles and 'tearstrengths were measured, the results being reported in Table 1X.

An impregnation liquor, comprising 0.2 ml of Emulsion H, 0.2 ml of a 1percent aqueous solution of monoethanolamine, and 199.6 ml of water, washeated to 60C and a 10 g hank of scoured cellulose diacetate continuousfilament yarn was immersed in the liquor, which was kept at 60C for 30minutes, the yarn being moved continuously in the liquor. The hank wasremoved, spun in a spin dryer, and dried at C. Comparison with untreatedyarn showed that a pleasing softening effect had been imparted to theyarn treated in accordance with the process of this invention.

EXAMPLE 11 Samples of a bleached cotton poplin (108 g per sq. metre)were padded with Liquors 17-21 so that the uptake was 70 percent. Thecompositions of the liquors, expressed in grams per litre of water, wereas follows:

Liquor l7 l8 19 20 21 22 Aminoplast B 120 120 120 120 120 MgCl .6H O l818 18 18 18 18 Emulsion H 20 Emulsion D 20 Emulsion E 2 Emulsion F 20Emulsion 1 20 The samples were dried for 10 minutes at 70C on tenterframes to their original dimensions and then cured by heating at C for 3/2 minutes. The crease angles and tear strengths of the patterns weremeasured. The samples were washed 5 times in an English ElectricReversomatic washing machine set on programme 2 (60C wash) using anaqueous solution containing 2g/l soap and 0.8g/1 soda ash, and thentumbledried. The crease angle and tear strength were again measured: theresults are given in Table X.

Tests also showed that the thiol did not interfere with the non-chlorineretentive properties of the resin.

EXAMPLE 12 Samples of a bleached cotton poplin (tear strength 792g) werepadded with Liquor l to 70 percent expression, dried on tenter frames totheir original dimensions, and cured by heating for 3 /2 minutes at160C. Next, some of the samples were padded with a 1.45 percent solutionof the Thiol or Polyol A in trichloroethylene to 138 percent pick-up.The trichloroethylene solutions also contained 0.029 percent ofdiethylentriamine as curing catalyst. The patterns were dried at 70C ontenter frames to their original dimensions and were then allowed to cureat room temperature for '1 week. The crease angle and tear strength weremeasured and are recorded in Table XI.

TABLE XI Treated with Crease angle Tear strength (g) Untreated 46 792Liquor 1 only 7 108 2111 Liquor l Thiol A 121 Z52 Liquor l Thiol G 124304 Liquor 1 Polyul A 106 312 This example illustrates that treatmentwith Polyol A improves only the tear strength whereas that with thethiols improves both the crease angle and the tear strength.

EXAMPLE 13 Cotton poplin samples were padded with 1.45 percent solutionof Thiol A in trichloroethylene to 138 percent pick up. In some casesthe solutions also contained curing catalysts. The patterns were driedat 70C to their original dimensions on tenter frames and they were thenkept at room temperature for 1 week to allow the thiol to cure. Thesamples were then treated with Liquor 1 to 70 percent pick-up; dried at70C to their original dimensions, and finally cured by heating for 3 /2minutes at 160C. Some samples were washed three times as described inExample 1 l. Crease angles and tear strength measurements of the treatedpatterns are recorded in Table XII.

aminoplastnNext, some of these samples were padded with a 1.27 percentsolution of a thiol and 0.0254 percent of diethylenetriamine intrichloroethylene, the

. pick-up of the thiol being 2 percent. They were dried as before, andleft at room temperature for 4 days. The crease angles and tear strengthwere measured, as shown in Table XIVP I Poplin samples were padded witha 1.46 percent solution of the thiol or Polyol A in trichloroethylene to2 percent pick-up of thiol or Polyol A. The samples were dried for 10minutes at 70C at their original dimensions on tenter frames. They werethen treated with Liquor l to 70 percent expression, dried as before,and cured for 3 /2 minutes at 160C. Some samples were TABLE XII Treatedwith (7( catalyst Crease angle Tear strength (g) (on weight of cotton)Un- Washed Unwashed washed washed Untreated 46 792 Liquor 1 only 108 98210 204 Thiol A Liquor 1 121 110 268 328 Thiol A Liquor 1 0.17: Coppernaphthenate(87rCu) 132 1 17 208 268 Thiol A Liquor 1 0.2% Diisopropylxanthogen disulphide 128 1 18 248 280 EXAMPLE l4 washedthree times bythe procedure described in Ex- A 50:50 cotton-polyester plain weavefabric was padded with one of Liquors 23-25 to 70 percent pick-up, driedat its original dimensions on tenter frames at 60C, and finally heatedfor 10 minutes at 170C. The crease angles and tear strength weremeasured and are recorded in Table XIII, as are the compositions of theliquors.

TABLE x111 Liquor Untreated 23 24 25 Aminoplast C (g/l) 150 150 150 MgCl.6H O(g/l) 20 20 20 Emulsion 0 (g/l) Emulsion H (g/l) 30 Crease angle 94117 122 128 Tear strength (g) 1344 1320 1376 1368 EXAMPLE 15 Samples ofthe bleached cotton poplin used in Example 1 l were padded with liquor 1to 70 percent expression, dried on tenter frames to their originaldimensions, and heated for 3%: minutes at 160C to cure the ample II. Thecrease angles and tear strengths were measured and the results arerecorded in Table XV.-

Emulsions H and J to L were applied to 10g pieces of scoured cellulosediacetate by the following procedure. Samples of each of the emulsionswere first diluted times with water and treatment liquors were thenprepared by taking 100 g/l of each of the diluted emulsions andadjusting the pH to 4.0 with acetic acid. The fabrics were treated at aliquor ratio of 20:1 for 30 minutes at 60C. In some cases hydrogenperoxide sufficient to provide a concentration of 1 volume was Table XVIHandle (21) No H addition Emulsion (b) H O; addition ra -m unorowwUntreated EXAMPLE l8 Emulsion H was applied to scoured cellulosediacetate under a variety of conditions. The emulsion was first diluted100 times with water and treatment liquors 26-29 were prepared accordingto Table XVII. Pieces (10g) of cellulose diacetate were treated for 30minutes at 60C. When a curing catalyst (hydrogen peroxide orN,N'-diethylthiourea) was used, it was added after minutes. The patternswere spun, dried, and conditioned, and handle assessments were carriedout as described in Example 17. Apart from Liquor 26, all the liquorswere completely exhausted at the end of the treatment. The results aregiven in Table XVII.

Table XVII Treatment Liquor 26 27 28 2 Diluted emulsion H (g) 20 20 20Aqueous Acetic acid. 571 (ml) 2 2 2 Aqueous hydrogen peroxide 20 vol.strength (ml) l0 N.N'-diethylthiourea (g) 0.25 Handle 2-3 2 2 2 EXAMPLE19 In this Example cotton poplin is cross-linked under wet conditions toimprove the wet-crease recovery. Cotton poplin as used in Example 16 waspadded to 70 percent retention with an aqueous liquor containing 300gper litre Aminoplast C and 100 ml per litre concentrated hydrochloricacid (36% w/w). The patterns were rolled up smoothly over a glass roller(5 cm diameter) and tightly wrapped in polyethylene sheet to preventescape of moisture. The roller was held horizontally and slowly rotatedfor 18 hours to ensure homogeneous treatment. The cloth was well rinsedwith water, then with an aqueous solution containing 5g/1 sodiumcarbonate, then with water, and dried. Some of the patterns were thenpadded to 70 percent retention with an aqueous solution containingeither 22 30g/l of Emulsion A, or 30g/l of Emulsion A plus l5g/l ofmonoethanolamine. They were dried for 10 minutes at C and the tearstrength and wet and dry crease recovery properties were determined onconditioned samplesf TABLE XVIII Wet crease Dry crease Tear Treatmentrecovery recovery strength (g) Aminoplast C only 92 47 404 Aminoplast CI06 59 436 Emulsion A Aminoplast C Emulsion A l 17 55 440Monoethanolamine Untreated 50 50 856 We claim:

1. A process for modifying hydroxy-containing cellulosic fibres whichcomprises 1. treating the fibres, free from keratinous material, A. witha polythiol having up to six thiol groups per molecule and a molecularweight between about 400 and about 10,000, wherein the polythiol has theformula p is a positive integer of at least 2 and at most 6, q is zeroor a positive integer of four or less, selected so that (p+q) equals atleast 2 and at most 6,

each alkylene group contains a chain of at least 2 and at most 6 carbonatoms between consecutive oxygen atoms,

R is an aliphatic radical containing at least 2 carbon atoms, and

X is an aliphatic radical containing at least one thiol group, and B.with an aminoplast which is free from ethylenic unsaturation, and

2. curing the polythiol and the aminoplast on the fibres.

2. The process of claim 1, wherein q is zero or 1, p is 2 to 6, providedthat when q is l, p is 2, R is an aliphatic hydrocarbon radical havingat least 3 and at most 6 carbon atoms, and X is an aliphatic radical ofthe formula C,,H ,,SH, wherein u is l or 2.

3. The process of claim 1, wherein the polythiol is selected from thegroup consisting of those of the formulae:

( CH2 (OC H O. co. C H SI-I CH2 (OC H O. co. C H S H 1 c o. H cit o v vs of (o H O e o n L C H O CO C H H CH (oc a v o. co. C H oH (c CH H ch(OC H O.CO. c a sa I (III) (IV) CIH (OC H O-CO.C H SH C H (OC H O.CO.CI-I SH I z 1 a C'H (OC H OH CIH i (OC H OH i l i 5 CH (OC H O. co. c asa (CH f i i CH C H O. co. c a sa I c H L. 2 .l. (V) and (VI) CH 0C H0.0 S I 2 t 0 c a H CH CH (OC H O co c a sn CH c 0c 0. H H CO C H SH L28. c 2 (OC H O. co. C H SH in which a is zeroito, 2,

m is an integer of at least 1,

t is an integer of at least 2 and at most 3, and

u is a positive integer of at most 2.

4. The process of claim 3, wherein the polythiol is selected from thegroup consisting of those of the formulae:

I, wherein t is 3 and u is l;

lll, wherein t is 3 and u is l;

V, wherein a is 2, t is 4, and u is l; and

VI, wherein t is 3 and u is l, in which in is an integer of at least 1,said polythiol having an average molecular weight of at least 1000 andat most 7500.

5. The process of claim 1, wherein n is zero and, X is an aliphaticradical of the formula ca CHCH SH, 2 2

wherein,

R is a substituent selected from the group consisting of OH,(O-alkylene),-OH, -O.CO.C,,H ,,SH, and (O-alkylene), O.CO,C,,H ,,SH,

u is l or 2, and

v is a positive integer of at least 1. 6. The process of claim 5,wherein R is Ol-l or (O-alkylene),.OH, q is zero, p is 3 to 6, and thealkylene groups are C l-l or C l-l 7. The process of claim 6, wherein Ris OH, the alkylene groups are C l-l q is zero, p is 3, R is R is -CH -C3HCH and the average molecular weight is between about 700 and about7500.

8. The process of claim 1,'wherein there is used a weight of polythiolwhich is 0.1 to 3 percent of the weight of cellulosic fibres treated.

9; The process of claim 1,:in which a catalyst for curing the polythiolis also applied, said catalyst being selected from the group consistingof bases, siccatives, sulphur, sulphur-containing organic compounds inwhich the sulphur atoms are not exclusively present as mercaptan groups,free-radical catalysts, salts of heavy metals with acids having an acidstrength (log pK) l2. Hydroxyl-containing cellulosic fibrous materials.

free from keratinous material, bearing thereon a cured coating from 0.5to 15 percent by weight of a polythiol resin and an aminoplast free fromethylenic unsaturation, said polythiol resin having up to six thiolgroups per molecule and a molecular weight between about 400 and about10.000, the polythiol having the formula:

l (-o-a1k 1ene) OH l l l l q l R l a l T lt w l m l p l l l l 1 in whichm is a positive integer of at least 1, n is zero or 1,

p is a positive integer of at least 2 and at most 6, p q is zero or apositive integer of four or less, selected so that (p+q) equals at least2 and at most 6,

each alkylene group contains a chain of at least 2 and at most 6 carbonatoms between consecutive oxygen atoms,

R is an aliphatic radical containing at least 2 carbon atoms, and

X is an aliphatic radical containing at least one thiol group.

13. The cellulosic fibrous material of claim 12, wherein the polythiolis the polythiol defined in claim 2.

14. The cellulosic fibrous material of claim 12, wherein the polythiolis the polythiol defined in claim 3.

15. The cellulosic fibrous material of claim 12, wherein the polythiolis the polythiol defined in claim 4 16. The cellulosic fibrous materialof claim 12, wherein the polythiol is the polythiol defined in claim 5.

17. The cellulosic fibrous material of claim 12, wherein the polythiolis the polythiol defined in claim 6.

18. The cellulosic fibrous material of claim 12, wherein the polythiolis the polythiol defined in claim 7.

19. The cellulosic fibrous material of claim 12, bearing thereon (A) thepolythiol and (B) an aminoplast providing from 2 to equivalents of agroup selected from the class consisting of N-methylol, N- alkoxymethyl,and N-acetoxymethyl groups per thiol group equivalent of said polythiol.

1. A PROCESS FOR MODIFYING HYDROXY-CONTAINING CELLULOSIC FIBERS WHICHCOMPRISES
 1. TREATING THE FIBRES, FREE FROM KERATINOUS MATERIAL, A. WITHA POLYTHIOL HAVING UP TO SIX THIOL GROUPS PER MOLECULE AND A MOLECULARWEIGHT BETWEEN ABOUT 400 AND ABOUT 10,000, WHEREIN THE POLYTHIOL HAS THEFORMULA R(-(O-ALKYLENE)M-OH)Q(-(O-ALKYLENE)M-O-(CO)N-X)P IN WHICH M IS APOSITIVE INTEGER OF AT LEAST 1, N IS ZERO OR 1, P IS A POSITIVE INTEGEROF AT LEAST 2 AND AT MOST 6, Q IS ZERO OR A POSITIVE INTEGER OF FOUR ORLESS, SELECTED SO THAT (P+Q) EQUALS AT LEAST 2 AND AT MOST 6, EACHALKYLENE GROUP CONTAINS A CHAIN OF AT LEAST 2 AND AT MOST 6 CARBON ATOMSBETWEEN CONSECUTIVE OXYGEN ATOMS, R IS AN ALIPHATIC RADICAL CONTAININGAT LEAST 2 CARBON ATOMS, AND X IS AN ALIPHATIC RADICAL CONTAINING ATLEAST ONE THIOL GROUP. AND B. WITH AN AMINOPLAST WHICH IS FREE FROMETHYLENIC UNSATURATION, AND
 2. CURING THE POLYTHIOL AND THE AMINOPLASTON THE FIBERS.
 2. curing the polythiol and the aminoplast on the fibres.2. The process of claim 1, wherein q is zero or 1, p is 2 to 6, providedthat when q is 1, p is 2, R is an aliphatic hydrocarbon radical havingat least 3 and at most 6 carbon atoms, and X is an aliphatic radical ofthe formula CuH2uSH, wherein u is 1 or
 2. 3. The process of claim 1,wherein the polythiol is selected from the group consisting of those ofthe formulae:
 4. The process of claim 3, wherein the polythiol isselected from the group consisting of those of the formulae: I, whereint is 3 and u is 1; III, wherein t is 3 and u is 1; V, wherein a is 2, tis 4, and u is 1; and VI, wherein t is 3 and u is 1, in which m is aninteger of at least 1, said polythiol having an average molecular weightof at least 1000 and at most
 7500. 5. The process of claim 1, wherein nis zero and, X is an aliphatic radical of the formula
 6. The process ofclaim 5, wherein R3 is -OH or -(O-alkylene)vOH, q is zero, p is 3 to 6,and the alkylene groups are -C2H4- or -C3H6-.
 7. The process of claim 6,wherein R3 is OH, the alkylene groups are C3H6, q is zero, p is 3, R is8. The process of claim 1, wherein there is used a weight of polythiolwhich is 0.1 to 3 percent of the weight of cellulosic fibres treated. 9.The process of claim 1, in which a catalyst for curing the polythiol isalso applied, said catalyst being selected from the group consisting ofbases, siccatives, sulphur, sulphur-containing organic compounds inwhich the sulphur atoms are not exclusively present as mercaptan groups,free-radical catalysts, salts of heavy metals with acids having an acidstrength (-log pK) below 5, and chelates of heavy metals.
 10. Theprocess of claim 1, which comprises treating the cellulosic fibres withthe polythiol at a temperature in the range 30* to 180*C.
 11. Theprocess of claim 1, which comprises treating the cellulosic fibres withthe polythiol in the form of a solution in an organic medium or in theform of an aqueous dispersion, solution, or emulsion. 12.Hydroxyl-containing cellulosic fibrous materials, free from keratinousmaterial, bearing thereon a cured coating from 0.5 to 15 percent byweight of a polythiol resin and an aminoplast free from ethylenicunsaturation, said polythiol resin having up to six thiol groups permolecule and a molecular weight between about 400 and about 10,000, thepolythiol having the formula:
 13. The cellulosic fibrous material ofclaim 12, wherein the polythiol is the polythiol defined in claim
 2. 14.The cellulosic fibrous material of claim 12, wherein the polythiol isthe polythiol defined in claim
 3. 15. The cellulosic fibrous material ofclaim 12, wherein the polythiol is the polythiol defined in claim
 4. 16.The cellulosic fibrous material of claim 12, wherein the polythiol isthe polythiol defined in claim
 5. 17. The cellulosic fibrous material ofclaim 12, wherein the polythiol is the polythiol defined in claim
 6. 18.The cellulosic fibrous material of claim 12, wherein the polythiol isthe polythiol defined in claim
 7. 19. The cellulosic fibrous material ofclaim 12, bearing thereon (A) the polythiol and (B) an aminoplastproviding from 2 to 75 equivalents of a group selected from the classconsisting of N-methylol, N-alkoxymethyl, and N-acetoxymethyl groups perthiol group equivalent of said polythiol.